Cryogenic Exfoliation of 2D Stanene Nanosheets for Cancer Theranostics

Stanene(Sn)-based materials have been extensively applied in industrial production and daily life,but their potential biomedical application remains largely unexplored,which is due to the absence of the appropriate and effective methods for fabricating Sn-based biomaterials.Herein,we explored a new approach combining cryogenic exfoliation and liquid-phase exfoliation to successfully manufacture two-dimensional(2D)Sn nanosheets(SnNSs).The obtained SnNSs exhibited a typical sheet-like structure with an average size of~100 nm and a thickness of~5.1 nm.After PEGylation,the resulting PEGylated SnNSs(SnNSs@PEG)exhibited good stability,superior biocompatibility,and excellent photothermal performance,which could serve as robust photothermal agents for multi-modal imaging(fluorescence/photoacoustic/photothermal imaging)-guided photothermal elimination of cancer.Furthermore,we also used first-principles density functional theory calculations to investigate the photothermal mechanism of SnNSs,revealing that the free electrons in upper and lower layers of SnNSs contribute to the conversion of the photo to thermal.This work not only introduces a new approach to fabricate 2D SnNSs but also establishes the SnNSs-based nanomedicines for photonic cancer theranostics.This new type of SnNSs with great potential in the field of nanomedicines may spur a wave of developing Sn-based biological materials to benefit biomedical applications.

Emerging vaccine nanotechnology: From defense against infection to sniping cancer

Looking retrospectively at the development of humanity, vaccination is an unprecedented medical landmark that saves lives by harnessing the human immune system. During the ongoing coronavirus disease 2019(COVID-19) pandemic, vaccination is still the most effective defense modality. The successful clinical application of the lipid nanoparticle-based Pfizer/BioNTech and Moderna mRNA COVID-19 vaccines highlights promising future of nanotechnology in vaccine development. Compared with conventional vaccines, nanovaccines are supposed to have advantages in lymph node accumulation,antigen assembly, and antigen presentation;they also have, unique pathogen biomimicry properties because of well-organized combination of multiple immune factors. Beyond infectious diseases, vaccine nanotechnology also exhibits considerable potential for cancer treatment. The ultimate goal of cancer vaccines is to fully mobilize the potency of the immune system as a living therapeutic to recognize tumor antigens and eliminate tumor cells, and nanotechnologies have the requisite properties to realize this goal.In this review, we summarize the recent advances in vaccine nanotechnology from infectious disease prevention to cancer immunotherapy and highlight the different types of materials, mechanisms, administration methods, as well as future perspectives.

Ultrathin tellurium nanosheets for simultaneous cancer thermo-chemotherapy

The emerging two-dimensional monoelemental materials(2D Xenes)have been commonly supposed as promising drug delivery carriers,photothermal and photodynamic therapeutic agents,biosensors,theranostics,and some other candidates for biomedical applications.Here,high-performance and bioactive ultrathin 2D Tellurium nanosheets(Te NSs)are prepared by a simple but efficient liquid-phase exfoliation approach.The as-obtained Te NSs possess a mean size of~90 nm and a mean thickness of~5.43 nm.The pegylation Te NSs(Te-PEG NSs)possess excellent biocompatibility and stability.The Te-PEG NSs could generate local hyperthermia with a remarkable photothermal conversion efficiency of about 55%under 808 nm laser irradiation.Additionally,Te-PEG NSs exhibit an extremely high loading capacity of chemo drug(~162%)owing to their ultra-high surface area and tumor microenvironment-triggered drug release superiority.The results of in vivo experiments show that the Te-PEG NSs have higher tumor elimination efficiency via the combination of photothermal and chemotherapy,comparing to any other single therapeutic modalities.Therefore,our work not only highlights the promising potentials of tellurene as an ideal anti-cancer platform but also expands the application of 2D Te for cancer nanomedicine.

Nano-bio interfaces effect of two-dimensional nanomaterials and their applications in cancer immunotherapy

The field of two-dimensional(2D)nanomaterial-based cancer immunotherapy combines research from multiple subdisciplines of material science,nano-chemistry,in particular nanobiological interactions,immunology,and medicinal chemistry.Most importantly,the"biological identity"of nanomaterials governed by bio-molecular corona in terms of bimolecular types,relative abundance,and conformation at the nanomaterial surface is now believed to influence blood circulation time,biodistribution,immune response,cellular uptake,and intracellular trafficking.A better understanding of nano-bio interactions can improve utilization of 2D nano-architectures for cancer immunotherapy and immunotheranostics,allowing them to be adapted or modified to treat other immune dysregulation syndromes including autoimmune diseases or inflammation,infection,tissue regeneration,and transplantation.The manuscript reviews the biological interactions and immunotherapeutic applications of 2D nanomaterials,including understanding their interactions with biological molecules of the immune system,summarizes and prospects the applications of 2D nanomaterials in cancer immunotherapy.

Black Phosphorus in Biological Applications:Evolutionary Journey from Monoelemental Materials to Composite Materials

CONSPECTUS:Understanding the evolutionary journey of monoelemental black phosphorus(BP)to BP-based composites plays a crucial role in expanding and advancing the development of BP in biological applications.Because of its exceptional unique structure and superior biological properties,BP has been extensively developed into various nanomaterials for different biological applications.However,the performance of BP alone cannot completely meet some specific requirements,and one possible route to harnessing its unique properties for different biological applications is to incorporate BP with a specific material to obtain an on-demand composite material.The manufacturing of such high-performance composites requires not only a full understanding of the structure and features of BP so that it could be perfectly incorporated with other materials or homogeneously distributed into various matrixes but also a clear biological effect of BP in different biological applications.Therefore,we summarize our recent work on BP-based high-performance composites for different biological applications,aiming to uncover(i)the evolutionary journey of BP from monoelemental materials to composite materials in biological applications and(ii)the interaction between BP and biological systems.Since the emergence of BP,BP-based materials have shown a prominent potential for technological applications as well as plenty of unexplored fundamental science.In particular,with the unlimited potential of BP in biological fields,it is desirable to take advantage of the useful performance of BP in composites through the combination of various functional materials for broadening its bioapplications.However,how to design and synthesize a BP-based composite with some specific performance remains a huge challenge due to the lack of an in-depth understanding of the interaction among BP,functional adjuvants,and physiological systems.BP-based nanosheets can selectively kill tumor cells via a reactive oxygen species(ROS)-mediated mechanism that indicates the biological effects of BP in physiological systems.Understanding the nanobio interaction of monoelemental BP materials can better make clear its fate in physiological systems,thereby contributing to the introduction of different functional adjuvants to decorate BP to obtain highperformance BP-based composite for different bioapplications.In addition,the functionalization or decoration of BP to form an additivesupported BP-based composite will further augment the performance of BP-based nanomaterials and broaden their bioapplication range.Owing to its high specific surface area and strong metal ion binding ability,BP nanosheets can serve as an ideal matrix to incorporate with small molecular drugs,metal ions,or metal nanostructures to obtain a multifunctional BP-based composite with enhanced properties for effective cancer therapy and photo/biocatalytic CO2 reduction.The combination of BP and the biomimetic matrix can also augment the performance of BP-based composites;therefore,fibrin gel with strong tissue healing could serve as an artificial skin to endow BP-based fibrin gel with excellent antibacterial ability,analgesia,and wound healing for diabetic ulcer therapy.Finally,we also outlook the future development and challenges as well as the clinical application prospect of an additive-supported BP-based composite.

The marriage of Xenes and hydrogels:Fundamentals,applications,and outlook

Hydrogels have blossomed as superstars in various fields,owing to their prospective applications in tissue engineering,soft electronics and sensors,flexible energy storage,and biomedicines.Two-dimensional(2D)nanomaterials,especially 2D mono-elemental nanosheets(Xenes)exhibit high aspect ratio morphology,good biocompatibility,metallic conductivity,and tunable electrochemical properties.These fascinating characteristics endow numerous tunable application-specific properties for the construction of Xene-based hydrogels.Hierarchical multifunctional hydrogels can be prepared according to the application requirements and can be effectively tuned by different stimulation to complete specific tasks in a spatiotemporal sequence.In this review,the synthesis mechanism,properties,and emerging applications of Xene hydrogels are summarized,followed by a discussion on expanding the performance and application range of both hydrogels and Xenes.